Generally, traffic light control systems have been specifically designed to operate with incandescent or halogen lamps. Both of these lamp types are relatively high power consumption devices. More recently, the use of LED traffic lamps has found favor for many reasons; including longer life expectancies than previously used lamps, as well as their operation at significantly lower energy consumption rates.
An issue has arisen, however, in that some specific street traffic light controllers expect a load power consumption greatly exceeding that of an LED traffic lamp. In these cases, simply replacing the normally used incandescent or halogen lamp with an LED lamp unit can cause the controller to malfunction or otherwise decide that the lamp unit is burned out and, thus, stop sending AC power signals to the traffic lamp or operate the traffic lamp in a mode in which the “red” lamp unit flashes repeatedly. These situations can cause dangerous conditions for motorists and pedestrians.
In view of these known issues, it would be advantageous, therefore, to provide a circuit for use with LED traffic lamps that will allow existing street traffic light controllers to continue normal operations using LED or other types of low power consumption lamp units.